Motivation

Traditionally providers of OAuth endpoints have relied upon cut-and-paste as
the way users of their service move the client id and secret from a
registration page into working code. That can be error prone, along with it
being an incomplete picture of all the information that is needed to get OAuth
2.0 working, which requires knowing all the endpoints and configuring a
Redirect Endpoint. If service providers start providing a downloadable
client_secrets.json file for client information and client libraries start
consuming client_secrets.json then a large amount of friction in implementing
OAuth 2.0 can be reduced.